In failsafe systems in particular, e.g. in industrial automation equipment, errors of all types must be detected with a high degree of probability and must be controlled such that, from the safety engineering perspective, they do not initiate an unacceptable response but at most a failsafe response. In such systems this applies especially to communication, e.g. via field buses. Communication in known field bus systems is conventionally set up according to the ISO/OSI model, that is to say, a distinction is made between different layers of communication, from the physical layer at the lowest level to the application layer at the highest level. With the known failsafe profile Profisafe, which is an extension of the known industry standard Profibus, communication is achieved with the requisite safety especially by the addition of a further failsafe layer known as the safety layer to the known ISO/OSI layers. This failsafe layer incorporates components of the communication system that is critical with regard to safety, e.g. addressing, watchdog timers, sequential control, signature, etc. Also in this safety layer of communication, a check value, e.g. what is known as a cyclic redundancy check (CRC) value, is generated using the data to be communicated. The purpose of this check value is to detect errors with the required probability. Thus, for example, a residual error rate for safety applications of less than 10−9 per hour can be guaranteed. The use of a check value serves to guarantee data integrity in data communication or data storage. Thus a value, in the simplest case a checksum, is determined from data of a message with a suitable method, e.g. is calculated. The resultant value is then co-stored or co-transmitted as a check value. The receiver of the message can likewise determine a check value from the data and can compare the said value with the co-transmitted check value of the transmitter. If the two check values are different, there is an error, especially a transmission error. If the two check values are identical, then there is a high degree of probability that the message has been correctly transmitted.